How to Upgrade from an HZ311 Thermostat to an Ecobee Smart Thermostat

If you want to move from a Honeywell HZ311 zone panel to an Ecobee thermostat but aren’t sure how to do it, read on. To replace the HZ311 thermostat, which is not a thermostat itself, the process is not as easy as replacing a regular thermostat. This guide will show you how to switch out an HZ311 thermostat for an Ecobee thermostat or add an Ecobee to your current zoned system so that it works well.

Understanding the HZ311 System

The Honeywell HZ311 zone panel is part of a zoned HVAC system, meaning it controls multiple zones (or areas) in your home. Each zone has its own thermostat that sends signals to the HZ311 panel, which then controls dampers to regulate airflow and temperature in different areas.

Key Features of the HZ311:

Works with conventional forced-air HVAC systems
Controls up to three zones
Uses 24V power and communicates with thermostats
Controls motorized dampers that regulate airflow per zone

Challenges of Replacing HZ311 with Ecobee:

There is only one zone on the Ecobee. If the HZ311 controls more than one zone in your home, switching it with an Ecobee will get rid of the zones unless you take other steps.
The wiring for HVAC needs to be changed. Like most single-zone thermostats, the wiring in a HZ311 device is not the same.
Change the damper. Ecobee doesn’t allow powered dampers by default, but the HZ311 does.

How to Change an HZ311 Thermostat to an Ecobee One

Step 1: Determine Your HVAC System Type

Before making the switch, identify the type of HVAC system you have:

Single-stage or multi-stage heating/cooling
Gas furnace, heat pump, or electric system
Presence of motorized dampers

Check your HVAC system manual or inspect the existing wiring to confirm compatibility with Ecobee.

Step 2: Decide on Your Installation Approach

You have two main options when switching from an HZ311 system to an Ecobee:

Replace the entire zoned system with a single Ecobee thermostat (removing zoning)
Keep the zoning system and install multiple Ecobee thermostats

Option 1: Removing the Zoning System (Simplest Approach)

If you decide to remove the zoning system entirely and use only a single Ecobee thermostat, follow these steps:

Turn off power to the HVAC system. Locate the breaker that powers your HVAC and switch it off.
Remove the HZ311 panel. Open the wiring connections and label each wire before disconnecting.
Identify the main thermostat wiring. Find the wires running from the main thermostat location to the HVAC control board.
Connect the Ecobee thermostat directly to the HVAC system. Follow the Ecobee wiring guide to match the appropriate terminals:
- R (Power)
- C (Common)
- W (Heat)
- Y (Cooling)
- G (Fan)
Cap off extra zone wires. Any unused wiring that ran to secondary zones can be capped off and left unused.
Power on the HVAC system and set up the Ecobee thermostat. Follow Ecobee’s installation instructions for initial setup and calibration.

Option 2: Keeping Zoning and Installing Multiple Ecobee Thermostats

If you want to retain zoning, you’ll need to replace each zone’s thermostat with an Ecobee thermostat while keeping the HZ311 panel intact.

Turn off power to the HVAC system. Safety first—switch off the breaker.
Check thermostat wiring. Remove the existing thermostats and label all wires.
Install an Ecobee thermostat for each zone.
- Connect the wires from each zone to the corresponding terminals on the Ecobee.
- Ensure each Ecobee is powered correctly (C-wire required for constant power).
Verify the damper control settings on the HZ311. The zone panel will continue to operate dampers based on signals from the Ecobee thermostats.
Set up Ecobee thermostats. Follow Ecobee’s guided setup to configure heating, cooling, and fan settings.
Power on and test the system. Ensure each zone responds correctly to temperature changes.

Step 3: Configure Smart Features

Once your Ecobee thermostat(s) are installed, take advantage of its smart features:

Remote Sensors: If removing zoning, Ecobee’s SmartSensors can help regulate temperatures in different rooms.
Home/Away Mode: Automatically adjusts temperature when you’re away to save energy.
Smart Recovery: Learns how long your home takes to heat/cool and adjusts schedules accordingly.

Step 4: Test and Monitor the System

After installation, run a full test:

Check heating and cooling operations. Ensure the Ecobee correctly controls the furnace, AC, and fan.
Monitor damper operation (if zoning is retained). Make sure each zone receives airflow as expected.
Test SmartSensor placement. If using Ecobee sensors, adjust their locations for balanced comfort.

Troubleshooting Common Issues

1. Ecobee Not Powering On

Check if a C-wire (common wire) is connected. Without a C-wire, Ecobee may not get enough power.
Use the Ecobee Power Extender Kit (PEK) if your system lacks a C-wire.
Ensure HVAC power is turned on at the breaker.

2. Some Zones Are Not Getting Heat or AC

If you kept the HZ311 panel, verify that the dampers are opening and closing properly.
Make sure each zone’s Ecobee is set to the correct heating/cooling mode.

3. Ecobee Cycles On and Off Too Frequently

Adjust the Heat Differential Temperature and Cool Differential Temperature in the Ecobee settings to prevent short cycling.
Check the HVAC filter and ducts for blockages.

Conclusion

It takes careful planning to switch from a HZ311 zoning system to an Ecobee thermostat. For zoned heating and cooling, it’s best to get more than one Ecobee device. You can get rid of the zoned panel and put a single Ecobee thermostat to make your system simpler, but this may change the balance of airflow.

If you follow the steps in this guide, you should be able to get a smart thermostat and keep controlling your heating and cooling well. Enjoy how easy Ecobee is to use, how much energy it saves, and how modern it is.